Chapter 4: Installing the HostRAID Controller and Disk Drives l 31The number of disk drives is limited to the number of slots available on the backplane. Somebackplanes have embedded SAS expanders and can support up to 128 end devices. For moreinformation about expander connections, see page 31.1 Connect one or more internal SAS or SATA disk drives to the backplane. Refer to yoursystem’s documentation for more information.2 Use an internal SAS cable to connect the SAS HostRAID controller to the backplane.3 When all internal disk drives have been installed and connected, close your computercabinet, reconnect the power cord.Installing the SAS HostRAID Controller to a SAS ExpanderYou can use a SAS expander to connect multiple disk drives to your SAS HostRAID controller(or to multiple SAS HostRAID controllers). Commands can be sent down one link and datareturned on another in a separate connection to increase fault tolerance. Using a SAS expanderand dual-port SAS drives and SATA drives with 2-port adapters, you can design redundantsystems for maximum fault-tolerance.To install the HostRAID controller to a SAS expander:1 Using the appropriate cable, connect the SAS HostRAID controller to the expander’s PHYconnector.2 Connect a cable from the expander’s PHY connector to a disk drive.Disk drives onbackplaneController connectedto backplane withfan-out cableInternal SAS connectorSAS fan-out cableExternal SASconnector